On Mon, 2019-12-23 at 18:09 +0100, Paolo Bonzini wrote: > On 23/12/19 15:48, Liran Alon wrote: > > > Should userspace expose the CR pining CPUID feature bit, it must > > > zero CR > > > pinned MSRs on reboot. If it does not, it runs the risk of having > > > the > > > guest enable pinning and subsequently cause general protection > > > faults on > > > next boot due to early boot code setting control registers to > > > values > > > which do not contain the pinned bits. > > > > Why reset CR pinned MSRs by userspace instead of KVM INIT handling? > > Most MSRs are not reset by INIT, are they? > As far as I can tell, KVM doesn't know if the guest is rebooted. Userspace uses the sregs and set MSRs ioctls to reset state. kvm_vcpu_reset is called on non-boot CPUs. kvm_vcpu_init isn't called on reboot.
